chore: HTML5 anchors compilant <a name= > <a id= (#6730)

* HTML5 anchors compilant `<a name=>` > `<a id=` for books

* HTML5 anchors compilant `<a name=>` > `<a id=` for courses

* HTML5 anchors compilant `<a name=>` > `<a id=` for contribs

* HTML5 anchors compilant `<a name=>` > `<a id=` for casts

* HTML5 anchors compilant `<a name=>` > `<a id=` for cheats

* HTML5 anchors compilant `<a name=>` > `<a id=` for interactives

* HTML5 anchors compilant `<a name=>` > `<a id=` for playgrounds

Author: davorpa

books/free-programming-books-ar.md

@@ -36,7 +36,7 @@
 * [مدخل إلى الذكاء الاصطناعي وتعلم الآلة](https://academy.hsoub.com/files/17-%D9%85%D8%AF%D8%AE%D9%84-%D8%A5%D9%84%D9%89-%D8%A7%D9%84%D8%B0%D9%83%D8%A7%D8%A1-%D8%A7%D9%84%D8%A7%D8%B5%D8%B7%D9%86%D8%A7%D8%B9%D9%8A-%D9%88%D8%AA%D8%B9%D9%84%D9%85-%D8%A7%D9%84%D8%A2%D9%84%D8%A9/) - Mohamed Lahlah (PDF)
 
 
-### <a name="csharp"></a>C#&lrm;
+### <a id="csharp"></a>C#&lrm;
 
 * [سبيلك المختصر لتعلم لغة c#&lrm; - برمجة الواجهات](https://www.mobarmijoun.com/2014/04/c_19.html) - Khaled Al-Saadani (Arab Coders Academy) (PDF)
 

books/free-programming-books-bg.md

@@ -16,14 +16,14 @@
 * [ANSI C - Пълен справочник](https://progstarter.com/index.php?option=com_content&view=article&id=9&Itemid=122&lang=bg) - Димо Петков
 
 
-### <a name="csharp"></a>C\#
+### <a id="csharp"></a>C\#
 
 * [Основи на програмирането със C#](https://csharp-book.softuni.bg) - Светлин Наков и колектив
 * [Принципи на програмирането със C#](https://introprogramming.info/intro-csharp-book) - Светлин Наков, Веселин Колев и колектив
 * [Програмиране за .NET Framework](https://www.devbg.org/dotnetbook) - Светлин Наков и колектив
 
 
-### <a name="cpp"></a>C++
+### <a id="cpp"></a>C++
 
 * [Основи на програмирането със C++](https://cpp-book.softuni.bg) - Светлин Наков и колектив
 

books/free-programming-books-cs.md

@@ -32,13 +32,13 @@
 * [Bash očima Bohdana Milara](http://i.iinfo.cz/files/root/k/bash_ocima_bohdana_milara.pdf) (PDF)
 
 
-### <a name="csharp"></a>C\#
+### <a id="csharp"></a>C\#
 
 * [Programovací jazyk C#](http://www.cs.vsb.cz/behalek/vyuka/pcsharp/text.pdf) - Marek Běhálek (PDF)
 * [Systémové programování v jazyce C#](https://phoenix.inf.upol.cz/esf/ucebni/sysprog.pdf) (PDF)
 
 
-### <a name="cpp"></a>C++
+### <a id="cpp"></a>C++
 
 * [Moderní programování objektových aplikací v C++](https://akela.mendelu.cz/~xvencal2/CPP/opora.pdf) (PDF)
 * [Objektové programování v C++](http://media1.jex.cz/files/media1:49e6b94e79262.pdf.upl/07.%20Objektov%C3%A9%20programov%C3%A1n%C3%AD%20v%20C%2B%2B.pdf) (PDF)

books/free-programming-books-de.md

@@ -67,13 +67,13 @@ Dirk Loser, Clemens Tamme, Philipp Schweinzer (PDF)
 * [Softwareentwicklung in C](https://web.archive.org/web/20190214185910/http://www.asc.tuwien.ac.at/~eprog/download/schmaranz.pdf) - Klaus Schmaranz (PDF)
 
 
-### <a name="csharp"></a>C\#
+### <a id="csharp"></a>C\#
 
 * [Programmieren in C#: Einführung](http://www.highscore.de/csharp/einfuehrung)
 * [Visual C# 2012](http://openbook.rheinwerk-verlag.de/visual_csharp_2012) - Andreas Kühnel (Online)
 
 
-### <a name="cpp"></a>C++
+### <a id="cpp"></a>C++
 
 * [Die Boost C++ Bibliotheken](http://dieboostcppbibliotheken.de) - Boris Schäling (Online)
 * [Lean Testing für C++-Programmierer (2018)](https://www.assets.dpunkt.de/openbooks/Openbook_Lean_Testing.pdf) - Andreas Spillner, Ulrich Breymann (PDF)

books/free-programming-books-dk.md

@@ -12,12 +12,12 @@
 * [Programmering i C](http://people.cs.aau.dk/~normark/c-prog-06/pdf/all.pdf) - Kurt Nørmark (PDF)
 
 
-### <a name="csharp"></a>C\#
+### <a id="csharp"></a>C\#
 
 * [Object-oriented Programming in C#](http://people.cs.aau.dk/~normark/oop-csharp/pdf/all.pdf) - Kurt Nørmark (PDF)
 
 
-### <a name="cpp"></a>C++
+### <a id="cpp"></a>C++
 
 * [Notes about C++](http://people.cs.aau.dk/~normark/ap/index.html) - Kurt Nørmark (HTML)
 

books/free-programming-books-el.md

@@ -14,7 +14,7 @@
 * [Διαδικαστικός προγραμματισμός](https://repository.kallipos.gr/bitstream/11419/1346/1/00_master%20document_KOY.pdf) - Μαστοροκώστας Πάρις (PDF)
 
 
-### <a name="cpp"></a>C++
+### <a id="cpp"></a>C++
 
 * [Εισαγωγή στη C++](http://www.ebooks4greeks.gr/2011.Download_free-ebooks/Pliroforikis/glossa_programmatismoy_C++__eBooks4Greeks.gr.pdf) (PDF)
 * [Προγραμματισμός με τη γλώσσα C++](https://repository.kallipos.gr/bitstream/11419/6443/1/00_master_document-KOY.pdf) - Θεόδωρος Αλεβίζος (PDF)

books/free-programming-books-es.md

@@ -135,7 +135,7 @@
 * [Introducción a la programación con C](http://repositori.uji.es/xmlui/bitstream/handle/10234/24306/s29.pdf) (PDF) (descarga directa)
 
 
-### <a name="cpp"></a>C++
+### <a id="cpp"></a>C++
 
 * [Aprenda C++ avanzado como si estuviera en primero](https://web.archive.org/web/20100701020037/http://www.tecnun.es/asignaturas/Informat1/AyudaInf/aprendainf/cpp/avanzado/cppavan.pdf) (PDF)
 * [Aprenda C++ básico como si estuviera en primero](https://web.archive.org/web/20100701020025/http://www.tecnun.es/asignaturas/Informat1/AyudaInf/aprendainf/cpp/basico/cppbasico.pdf) (PDF)

books/free-programming-books-et.md

@@ -18,7 +18,7 @@
 * [Programmeerimiskeel C](https://et.wikibooks.org/wiki/Programmeerimiskeel_C) - Wikiõpikud
 
 
-### <a name="csharp"></a>C\#
+### <a id="csharp"></a>C\#
 
 * [Microsoft Visual Studio Code ja C#](https://digiarhiiv.ut.ee/Ained/Doc/VFailid/CSharp_ja_VS.pdf) - Kalle Remm (PDF)
 

books/free-programming-books-fi.md

@@ -29,12 +29,12 @@
 * [Ohjelmoinnin perusteet ja C-kieli](http://cs.stadia.fi/~silas/ohjelmointi/c_opas) - Simo Silander
 
 
-### <a name="csharp"></a>C\#
+### <a id="csharp"></a>C\#
 
 * [Ohjelmointi 1: C#](https://jyx.jyu.fi/bitstream/handle/123456789/47417/978-951-39-4859-7.pdf) - Martti Hyvönen, Vesa Lappalainen, Antti-Jussi Lakanen (PDF)
 
 
-### <a name="cpp"></a>C++
+### <a id="cpp"></a>C++
 
 * [C++](https://fi.wikibooks.org/wiki/C%2B%2B) - Wikikirjasto
 * [C++-ohjelmointi](https://www.ohjelmointiputka.net/oppaat/opas.php?tunnus=cpp_ohj_01)

books/free-programming-books-he.md

@@ -26,7 +26,7 @@
 * [ארגון המחשב ושפת סף](https://data.cyber.org.il/assembly/assembly_book.pdf) – ברק גונן, המרכז לחינוך סייבר (PDF)
 
 
-### <a name="csharp"></a>C\#
+### <a id="csharp"></a>C\#
 
 * [מבוא לתכנות בסביבת האינטרנט בשפת C#](https://meyda.education.gov.il/files/free%20books/%D7%9E%D7%91%D7%95%D7%90%20%D7%9C%D7%AA%D7%9B%D7%A0%D7%95%D7%AA%20%D7%91%D7%A1%D7%91%D7%99%D7%91%D7%AA%20%D7%94%D7%90%D7%99%D7%A0%D7%98%D7%A8%D7%A0%D7%98%20090216.pdf) – מט״ח (PDF)